Our invention relates to the catalytic removal of n-paraffins and organosulfur compounds from materials which contain hydrocarbons. One of the important fractions of crude petroleum is the gas oil fraction. It contains many compounds boiling from 200.degree. C. to 600.degree. C. The importance of this fraction is that it is the primary source of jet and diesel fuel, fuel oils, and lubricating oils. In the future, synthetic fuels produced from coal, shale, tar sands, heavy oils and other sources will produce gas oil range products.
The typical gas oil range feed contains both sulfur compounds and n-paraffins. The organosulfur compounds must be removed to avoid air pollution and corrosion problems. The molecular distribution of n-paraffins must be shifted from higher to lower molecular weights to reduce the pour point of the product so the product can flow under the conditions of use.
Many catalysts and processes have been proposed and used to desulfurize and dewax hydrocarbon containing feeds. U.S. Pat. No. 3,668,113, Burbidge et al., June 6, 1972, discloses a two-step process involving dewaxing with a mordenite catalyst followed by desulfurizing with a Group VI or VIII hydrogenation catalyst. U.S. Pat. No. RE 28,398 of U.S. Pat. No. 3,700,585, Chen et al., Oct. 24, 1972, discloses dewaxing oils using ZSM-5. U.S. Pat. No. 3,894,938, Gorring et al., July 15, 1975, discloses dewaxing a sulfur-containing gas oil with a ZSM-5 catalyst followed by conventional hydrodesulfurizing. U.S. Pat. No. 4,213,847, Chen et al., July 22, 1980, discloses hydrodewaxing in a distillation reaction column. U.S. Pat. No. 4,229,282, Peters et al., Oct. 21, 1980, discloses hydrodewaxing with a catalyst which contains a nickel/tungsten hydrogenation component and a ZSM-5 zeolite. U.S. Pat. No. 4,257,872, LaPierre et al., Mar. 24, 1981, discloses a dual bed process for upgrading refractory hydrocarbon feeds which involves hydrotreating followed by hydrocracking with an alkali-metal poisoned ZSM-5 zeolite.
Several other patents also relate to dewaxing hydrocarbon feeds. U.S. Pat. No. 3,852,189, Chen et al., Dec. 3, 1974, discloses liquid phase dewaxing using ZSM-5 zeolites. U.S. Pat. No. 3,968,024, Gorring et al., July 6, 1976, discloses dewaxing at low pressures using microcrystalline ZSM-5 zeolites. U.S. Pat. No. 4,149,960, Garwood et al., Apr. 17, 1979, discloses dewaxing gas oils using ZSM-5 zeolites and cofed water. U.S. Pat. No. 4,171,257, O'Rear et al., Oct. 16, 1979, discloses upgrading petroleum feeds and producing light olefins using ZSM-5 zeolites at low pressures. U.S. Pat. No. 4,135,540, Gorring et al., May 8, 1979, discloses upgrading shale oil by hydrotreating followed by hydrocracking the hydrotreater effluent with a ZSM-5 zeolite.